1. Field of the Invention
The present invention relates to a composition for stimulating osteogenesis and preventing reduction of a bone salt content, which can be used for therapy and prevention of osteoporosis, fracture and the like.
2. Description of the Related Prior Art
The osteoporosis is tends to give rise to lumbar pressure fracture, fracture of femoral neck and the like due to the reduction of the bone salt content per unit capacity which is the mode of a disease. These fractures are the main cause for old-aged person to be confined the bed for a long time. Further, postmenopausal estrogen secretion for women may reduce so that the bone salt content rapidly decreases, and they are susceptible to osteoporosis. Additionally, it is not easy to increase the reduced bone salt content, and it is difficult to treat the osteoporosis. Accordingly, it is important to prevent the osteoporosis. To this end, it is necessary to increase the bone salt content from the youth and to suppress rapid reduction of postmenopausal bone salt content. Also even in young people, diseases causing from calcium ponerty owing to unbalanced diet are increasing.
Ingestion of sufficient calcium from a meal and moderate exercises are important for the prevention of osteoporosis and diseases causing from calcium ponerty. To this end, various sources for supplying calcium have been developed. However, it has been known that intestinal absorption of calcium may be affected by the state of calcium salt and other coexisting foodstaffs. Studies of a calcium absorbing mechanism and developments of foodstaffs for stimulating the absorption thereof or preventing the reduction of bone salt content have been demanded.
Soybeans contain many kind of isoflavones which include daidzin, genistin, glystin and those having a malonyl group bonded thereto, and aglycon thereof. Recently, it has been reported that these ingredients have an anti-tumor activity, a female hormone-like activity and the like, upon which attention has been focused.
The absorption of isoflavone was examined for rats by supplying an isoflavone to confirm the absorption thereof in blood after ingestion of the feed (R. King, J. Nutr. 126: 176-183, 1996). Further, it has been also reported that the isoflavone thus orally administerd may increase the bone density of femur (Uesugi et al., Society of Nutritious Food In Japan, 1996).
Further, it has been reported by in vivo experiment (Metabolisum, 35, 773, 1986, Biochem. Pharmacol. 35, 773, 1986) and in vitro experiment (Biochem. Pharmacol., 36, 4007, 1987, 37, 4075, 1988) that zinc plays an important part as an active factor for stimulation of osteogenesis and for mineralization. Moreover, there is shown that zinc stimulates a bone protein synthesis (Biochem. Pharmacol., 37, 4075, 1988).